AutoCAD Guidance




Template

Create a template that you use each time you start a new drawing. Create a template that contains the required layers, textstyles, dimstyles and settings in the status bar or settings in the options menu. Without doubt can this template save your time, because you don't need to create the settings when you start a new drawing.



Standards for Technical Documentation

Use the standards that are recognized and accepted by the industry that you work in. The ISO standard are used internationally. ANSI standard are often used in USA. Text height 3, 5 or 2, 5 mm for dimensions or descriptive text. Text height 5 or 7 mm for headings. Small text height, 2, 5 mm in the title block. Bear in mind, that it must be readable on the print or plot.



Quickly Start a New Drawing

The QNEW command combined with a template can be the fastest way to start a new drawing. When you use the following settings, QNEW immediately starts a new drawing without displaying any dialog boxes or prompts, do the following:

1. Set the FILEDIA system variable to 1.

2. Set the STARTUP system variable to 0.

3. Bring Options dialog, switch to Files tab and specify QNEW template in Template Settings, Default Template File Name for QNEW.



Opening a AutoCAD drawing

The most obvious problem is that you can't open a drawing. Try the following techniques to solve the problem:

Find the autosave files (auto.sv$ by default) and rename them with a .DWG extension and try to open them. Use Windows search to find the autosave files , search with wildcard *.sv$. Rename the drawing's BAK (backup) file by changing its filename extension to .dwg and see if you can open that. If it works, EXPLODE the drawing after you insert it. Another thing you can do, that is to use the RECOVER command. Open a new drawing and choose File Drawing-> Utilities-> Recover. Choose the drawing from the dialog box and click OK. If you can open a drawing, but get an error message, then use the AUDIT command. You can find it right next to the RECOVER command on the File menu. AutoCAD tries to correct any errors. You can also open a new drawing with the "start from scratch option" to open a drawing with only a few settings. Finally, there is the possibility to use WBLOCK to save all the objects in the drawing as a new drawing file.



Drawing Limits in AutoCAD

The drawing limits are there for a reason. When you start a new drawing, then decide how much space do I need for my drawing. Think of it as the size of your drawing area. Then you can define drawing limits correctly. Type LIMITS enter. Type 0, 0 as lower left corner then type or click the coordinate for upper right corner.

Furthermore, the drawing limits defines the extent of ZOOM all. Tip: You can make a little space around the drawing frame, if you define drawing limits a inch outside the drawing frame. This makes it easier to do PLOT "window".



Precision in AutoCAD

The SNAP command makes it possible to draft precisely, when you are making a drawing in AutoCAD. Type SNAP enter. Now type 1 or you could type with decimals 0.1 Make a snap setting that is appropiate to the object's size. The result is that you drawing contains coordinates with rounded digits. F. ex. 200.50, 200.00. I believe most people prefer precise and rounded coordinates. Use OBJECT SNAP, OBJECT SNAP TRACKING and SNAP as much as possible to create accurate drawings.



Command Alias

A command alias is an abbreviation that you enter at the command prompt instead of entering the entire command name.

For example, you can enter a instead of to start the ARC command. An alias is different from a keyboard shortcut, which is a combination of keystrokes, such as CTRL+N for NEW.

An alias can be defined for any AutoCAD command, device driver command, or external command. The second section of the acad.pgp file defines command aliases. You can change existing aliases or add new ones by editing acad.pgp in an ASCII text editor. To open the PGP file, Click Tools menu - Customize - Edit Program Parameters (acad.pgp). The file can also contain comment lines preceded by a semicolon (;).

Before you edit acad.pgp, it would be a good precaution to create a backup so that you can restore it later, if needed.

To define a command alias, add a line to the command alias section of the acad.pgp file using the following syntax:

abbreviation,*command

where abbreviation is the command alias that you enter at the Command prompt and command is the command being abbreviated. You must enter an asterisk (*) before the command name to identify the line as a command alias definition.

If you can enter a command transparently, you can also enter its alias transparently. When you enter the command alias, the full command name is displayed at the Command prompt and the command is executed.

You can create command aliases that include the special hyphen (-) prefix, that accesses a command that displays a command prompt instead of a dialog box. Exclude the prefix (-) and you see a dialog box when you enter the command alias, surely only for those commands where a dialog box is accessible.

BH, *-BHATCH

BD, *-BOUNDARY

Note: You can't use command aliases in command scripts. It is not recommended to use command aliases in customization files.

If you edit acad.pgp while AutoCAD is running, enter reinit to use the revised file.



HELP SYSTEM

When you use the Help system, you can display and expand the table of contents to find adjacent topics. Click on the Contents tab in the left panel which will show a collapsed content and then click on the Concepts tab in the right panel.  This will expand the contents tree in the left panel.



Disappearing Hatch

If you open an R12 or earlier drawing in R14 or later, and can not see the hatching, then you need to check the FILLMODE setting. If FILLMODE is set to OFF, the hatching will not show. This is to speed up REGEN times. Make hatches visible by setting FILLMODE to ON.



Purge

The data from an AutoCAD drawing consumes the resources on a IT system. Therefore you must regularly remove unnecessary data from a drawing. You do this with the PURGE command. In older version before 2000 you have to write PURGE in command line, at the prompt "do you want to purge all objects? Type Yes, enter. In newer versions, you use a dialog box, selectively you choose what kind of objects you want to purge. Only use purge when the drawing is complete. Else you might remove layers or textstyles that you wanted to keep.



Design Center

I believe Design Center is a very useful tool. With Design Center you can find and reuse layers, layouts, linetypes, dim styles, text styles, hatches and blocks from other drawings. Certain parts of a drawing can be copied into another drawing easily. Choose the parts in right side of dialog box. Drag and drop the parts into the drawing area of the dwg file that you have open. Blocks can be categorized and used in the tool palette. Make a library of blocks or hatches in tool palettes. Simply click on a block from Design Center and drag it over to a tool palette, drop it when the cursor is above the gray area of a tool palette. This feature in AutoCAD is great, because it makes your work easier and saves a lot of time!





AutoCAD 3D Recommendations


Creating 3D wireframe models can be more challenging than creating 2D drawings. Here are some advice that will help you work efficiently:
  1. Create sufficient layers to organize your model. Turn off layers that you currently are not working with. That way you reduce the visual complexity of the model. Use different colors can help you differentiate between objects in various views.

  2. Create construction geometry to define the basic envelope of the model.

  3. Create and use multiple views, especially isometric views. Hence making visualization of the model easier. Additionally it becomes easier to select objects.

  4. Become familiar with the User Coordinate System - UCS. Learn how to make the XY plane in UCS parallel with another plane. Learn that Z is the depth in 3D space. The XY plane of the current UCS operates as a work plane to orient planar objects such as rectangles, circles and arcs. The UCS determines the plane of operation for moving, trimming and extending, offsetting, and rotating objects.

  5. Always use object snaps and snap, this will ensure the precision of your model.

  6. Use coordinate filters to easily locate points in 3D based on the location of points on other objects.



3D Rendering

To save time only render a preview in smaller output size 640 X 480. When making previews you can also use "render cropped region". Only use shadows, in final render. Use ray-traced reflections and refractions, when it is needed, namely in scenes with water, marble, glass and mirrors. Shadow mapping display more soft edges and require less rendering time. Ray-traced shadows have more accurate and hard edges. The ray-traced shadows also transmit color from transparent and translucent objects. However this shadow setting require more rendering time. Use only 1 or 2 lights in a scene. The excepting is indoor interior, where is many lamps and spotlights. Only use sunlight in a outdoor scene. If using sunlight, then adjust light intensity, time and date depending on the atmosphere you want to set. Use the necessary time to adjust falloff angle in cone of spotlight, light intensity and the angle from light source to target. Some scenery require that you combine point light with spotlight.

Read also web page about Rendering and Visualization in AutoCAD 2007

 



3D Performance

Type OPTIONS enter, click on System, then click on Performance Settings. Click on the small "check box" Adaptive degradation, so that it's ON. Next "check" all items below. In the dialog box "Adaptive Degradation and Performance Tuning" click Manual Tune. Next "check" to enable hardware acceleration and reset to recommended values, continue clicking OK, until you have exited all dialog boxes.



Benefits of using 3D Solids

There are certain benefits when you use 3D solids. From 3D solids you can read mass, volume, centroid, moments of inertia, products of inertia with the MASSPROP command. This information is not possible to get with a box build with surfaces. The exception here are regions. From these you can read area, centroid, moments of inertia and product of inertia. And it's easy to edit a solid with grips. Moreover, you can easily create holes, fillets and chamfers on a 3D solid. Additionally, you can use boolean operations on solids, like intersect, subtract and union. My advice: Always use 3D solids or regions, when it's possible in AutoCAD. In architectural design, use region for the floor. Because it's easier to get the area with the Massprop command.









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